Intertrial interval effects in classically conditioned fear to a discrete conditioned stimulus and to situational cues.

1974 ◽  
Vol 87 (3) ◽  
pp. 582-590 ◽  
Author(s):  
Wallace R. McAllister ◽  
Dorothy E. McAllister ◽  
Garry H. Weldin ◽  
Jeffrey M. Cohen
Keyword(s):  
Conditioned Stimulus ◽  
Intertrial Interval ◽  
Conditioned Fear ◽  
Situational Cues ◽  
Classically Conditioned

New Vistas on Amygdala Networks in Conditioned Fear

2004 ◽  
Vol 92 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Denis Paré ◽  
Gregory J. Quirk ◽  
Joseph E. Ledoux
Keyword(s):  
Brain Stem ◽  
Conditioned Fear ◽  
Current Model ◽  
Central Nucleus ◽  
Projection Neurons ◽  
Conditioned Freezing ◽  
Fear Potentiated Startle ◽  
Classically Conditioned ◽  
The Brain ◽  
Critical Site

It is currently believed that the acquisition of classically conditioned fear involves potentiation of conditioned thalamic inputs in the lateral amygdala (LA). In turn, LA cells would excite more neurons in the central nucleus (CE) that, via their projections to the brain stem and hypothalamus, evoke fear responses. However, LA neurons do not directly contact brain stem-projecting CE neurons. This is problematic because CE projections to the periaqueductal gray and pontine reticular formation are believed to generate conditioned freezing and fear-potentiated startle, respectively. Moreover, like LA, CE may receive direct thalamic inputs communicating information about the conditioned and unconditioned stimuli. Finally, recent evidence suggests that the CE itself may be a critical site of plasticity. This review attempts to reconcile the current model with these observations. We suggest that potentiated LA outputs disinhibit CE projection neurons via GABAergic intercalated neurons, thereby permitting associative plasticity in CE. Thus plasticity in both LA and CE would be necessary for acquisition of conditioned fear. This revised model also accounts for inhibition of conditioned fear after extinction.

Classically conditioned fear responses are preserved following unilateral temporal lobectomy in humans when concurrent US-expectancy ratings are used

2009 ◽  
Vol 47 (12) ◽  
pp. 2496-2503 ◽  
Author(s):  
Evelien Coppens ◽  
Adriaan Spruyt ◽  
Mathieu Vandenbulcke ◽  
Wim Van Paesschen ◽  
Debora Vansteenwegen
Keyword(s):  
Conditioned Fear ◽  
Temporal Lobectomy ◽  
Classically Conditioned
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